More Engine Help...0psi Compression
Thread Starter
Instructor
Joined: Feb 2012
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Sounds like rings. However....before doing anything, make sure the PCV valve/system is good. Hopefully with all the cranking, if you didn't unplug the injectors, you didn't wash down the cylinder walls. 
Head issues (ie valve seals, guides) are typically blue smoke at start-up or upon decel. Rings are blue smoke all the time.
Head issues (ie valve seals, guides) are typically blue smoke at start-up or upon decel. Rings are blue smoke all the time.
Whats your PCV doing?
Thats MUST be connected right or it WILL suck oil into the intake and burn it.
Its not a new build so they should be seated unless they were horribly damaged by running too long with the poor pressure from the loose mains.
As far as the oil pressure...Better get a mechanical gauge to confirm whats going on..that sounds strange. Slow climbing suggest a slow sender...ck the harness grounds, and sender connections. Remember, OP is whats left over AFTER the oil has traveled past the mains, rods and cam. If its climbing as it heats up (and thats what is really happening) that would suggest that something is leaking a LOT of oil until it heats up and seals better. best not to guess...get the mechanical gauge.
Thats MUST be connected right or it WILL suck oil into the intake and burn it.
Its not a new build so they should be seated unless they were horribly damaged by running too long with the poor pressure from the loose mains.
As far as the oil pressure...Better get a mechanical gauge to confirm whats going on..that sounds strange. Slow climbing suggest a slow sender...ck the harness grounds, and sender connections. Remember, OP is whats left over AFTER the oil has traveled past the mains, rods and cam. If its climbing as it heats up (and thats what is really happening) that would suggest that something is leaking a LOT of oil until it heats up and seals better. best not to guess...get the mechanical gauge.
It actually is a new build minus the 10min. or so run time with the low oil pressure. I don't have the PCV hooked up, I instead put a filtered breather on their instead.
Safety Car
Joined: Apr 2011
Posts: 3,660
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It was only cranked without injectors for a half dozen turns or so, so hopefully that isn't the issue. Would it be possible that the low oil pressure from the original rebuild cause cylinder wall scoring?
I will double check the oil pressure, sounds like a slow gauge to me, but I don't want to guess on that again It actually is a new build minus the 10min. or so run time with the low oil pressure. I don't have the PCV hooked up, I instead put a filtered breather on their instead.
I will double check the oil pressure, sounds like a slow gauge to me, but I don't want to guess on that again
It actually is a new build minus the 10min. or so run time with the low oil pressure. I don't have the PCV hooked up, I instead put a filtered breather on their instead.gotta do the PCV the way it was. That valve is necessary.
Otherwise, its just like a straw in a soda can....sucking the oil out as fast as the intake can draw it up. If you were to look inside you will see the intake and maybe the plenum sloppy wet with oil from being drawn in thru the pcv hoses.The hoses will be wet inside...
There WILL be some blowby...that will end IF the rings seat. That ain;t gonna happen if they keep getting soaked in oil.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
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From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
I bought a set of rings for my car, and installed them. It smoked like a banshee.
Turns out, the oil ring expander on cyl #8 was cut short on the machine when made. I had to take the engine all apart, but the ring manufacturer made good on the rings, and sent me a new set.
If yours is an 86, loosen the EGR tube on the manifold, and slip in a thin piece of metal to block off the EGR gas flow. then snug up the two bolts.
a bad #8 cyl will distribute oil to all cylinders.
1. your rings aren't scored.
2. your heads are ok.
3. your rings may not have seated.
did it smoke the last time with the loose bearings?
Another thing to check is rocker covers. Did you change rocker covers? If you did, the new ones may not have a oil baffle where the PCV valve is.
IF the baffle is missing, the oil from your pushrod may be squirting right at your pcv valve.
Turns out, the oil ring expander on cyl #8 was cut short on the machine when made. I had to take the engine all apart, but the ring manufacturer made good on the rings, and sent me a new set.
If yours is an 86, loosen the EGR tube on the manifold, and slip in a thin piece of metal to block off the EGR gas flow. then snug up the two bolts.
a bad #8 cyl will distribute oil to all cylinders.
1. your rings aren't scored.
2. your heads are ok.
3. your rings may not have seated.
did it smoke the last time with the loose bearings?
Another thing to check is rocker covers. Did you change rocker covers? If you did, the new ones may not have a oil baffle where the PCV valve is.
IF the baffle is missing, the oil from your pushrod may be squirting right at your pcv valve.
Last edited by coupeguy2001; Oct 23, 2012 at 12:16 AM.
Thread Starter
Instructor
Joined: Feb 2012
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naw....
gotta do the PCV the way it was. That valve is necessary.
Otherwise, its just like a straw in a soda can....sucking the oil out as fast as the intake can draw it up. If you were to look inside you will see the intake and maybe the plenum sloppy wet with oil from being drawn in thru the pcv hoses.The hoses will be wet inside...
There WILL be some blowby...that will end IF the rings seat. That ain;t gonna happen if they keep getting soaked in oil.
gotta do the PCV the way it was. That valve is necessary.
Otherwise, its just like a straw in a soda can....sucking the oil out as fast as the intake can draw it up. If you were to look inside you will see the intake and maybe the plenum sloppy wet with oil from being drawn in thru the pcv hoses.The hoses will be wet inside...
There WILL be some blowby...that will end IF the rings seat. That ain;t gonna happen if they keep getting soaked in oil.
I bought a set of rings for my car, and installed them. It smoked like a banshee.
Turns out, the oil ring expander on cyl #8 was cut short on the machine when made. I had to take the engine all apart, but the ring manufacturer made good on the rings, and sent me a new set.
If yours is an 86, loosen the EGR tube on the manifold, and slip in a thin piece of metal to block off the EGR gas flow. then snug up the two bolts.
a bad #8 cyl will distribute oil to all cylinders.
1. your rings aren't scored.
2. your heads are ok.
3. your rings may not have seated.
did it smoke the last time with the loose bearings?
Another thing to check is rocker covers. Did you change rocker covers? If you did, the new ones may not have a oil baffle where the PCV valve is.
IF the baffle is missing, the oil from your pushrod may be squirting right at your pcv valve.
Turns out, the oil ring expander on cyl #8 was cut short on the machine when made. I had to take the engine all apart, but the ring manufacturer made good on the rings, and sent me a new set.
If yours is an 86, loosen the EGR tube on the manifold, and slip in a thin piece of metal to block off the EGR gas flow. then snug up the two bolts.
a bad #8 cyl will distribute oil to all cylinders.
1. your rings aren't scored.
2. your heads are ok.
3. your rings may not have seated.
did it smoke the last time with the loose bearings?
Another thing to check is rocker covers. Did you change rocker covers? If you did, the new ones may not have a oil baffle where the PCV valve is.
IF the baffle is missing, the oil from your pushrod may be squirting right at your pcv valve.
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
I completely took out the pcv valve and all related hosing in the intake. Which hose are you talking about? If all the fittings on the intake were capped off, wouldn't that stop any oil from getting in? Not trying to sound like i'm talking down to you, I just don't fully understand.
I have not changed the valve covers recently, although the ones I have do not have oil baffles by the pcv valve. If the pcv was replaced by the breather, wouldn't this point be null? And it did smoke with the old bearings, but not nearly as much. Possibly the added pressure is forcing the oil to something were it wasn't going before?
I have not changed the valve covers recently, although the ones I have do not have oil baffles by the pcv valve. If the pcv was replaced by the breather, wouldn't this point be null? And it did smoke with the old bearings, but not nearly as much. Possibly the added pressure is forcing the oil to something were it wasn't going before?
Put it back the way it was when you found it. There is a good reason (many actually) why PCV is there and has been on EVERY engine since the late 60s? its been a long time.
Wanna tell me why its a good idea to eliminate PCV? I'm listen'n.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Yes..the crankcase is now PRESSURIZED. Congrats. Thats what so many folks have worked to avoid. Main seals blow, pan gaskets, oil gets forced where ever it can find a place to escape. PCV maintains NEGETIVE pressure (vacuum) in the crankcase so this will NOT happen. This also gets the toxic fumes OUT and prevents moisture from causing oxidization in the crankcase and degrading the oil faster and trapping more hydrocarbons. Your natural blow-by, now cannot escape. Theres your oil burning. When there is sufficient pressure UNDER the piston the blow-by cannot enter to be evacuated...thru PCV.
Put it back the way it was when you found it. There is a good reason (many actually) why PCV is there and has been on EVERY engine since the late 60s? its been a long time.
Wanna tell me why its a good idea to eliminate PCV? I'm listen'n.
Put it back the way it was when you found it. There is a good reason (many actually) why PCV is there and has been on EVERY engine since the late 60s? its been a long time.
Wanna tell me why its a good idea to eliminate PCV? I'm listen'n.
